1. Field of the Invention
The invention relates to a Redundant Array of Independent Disks (RAID) system, and more particularly to a system and method for reconstructing a RAID system.
2. Description of the Related Art
A RAID system is composed of multiple disks (for example, hard disks) with series or parallel connections that generates a tolerance (intolerance) array system to form a large virtual disk, thus increasing access speed, enhancing data security, and providing disk tolerance function.
The RAID systems comprise RAID-0, RAID-1, RAID-2, RAID-3, RAID-4, RAID-5, and RAID-6 systems. The RAID-5 is also a rotating parity array, an array system comprising at least more than 3 disks (for example, hard disks). The RAID-5 system is applicable that system load can be distributed to multiple disks so that data still can be recombined to keep the data integrity while one of the disks is damaged.
As described, in a host comprising the RAID-5 system, when one of the disks is damaged, the damaged disk is replaced by a new disk and data in the damaged disk is recombined in the new disk. Additionally, each disk can be swapped only for one time and the swapped disk cannot be used in other RAID-5 systems. When the disks in the host are all removed from and installed in the host with different sequence, the RAID-5 system cannot determine the disk sequence so that data in the disks cannot be recombined.
Additionally, when three disks (for example, disks 1, 2, and 3) are installed in the RAID-5 system, if the disk 2 is removed from and inserted in the RAID-5 system, the RAID-5 system may recognize the disk 2 as a new disk (for example, disk 4). Further, when the disk 2 is removed from the RAID-5 system and a new disk (for example, disk 5) is inserted in the position where the disk 2 is originally installed, the RAID-5 system may recognize the disk 5 as the disk 2. Thus, the RAID-5 system performs a data recovery operation that data in the disk 5 is deleted and data in the disk 2 is recovered using data in the disks 1 and 3, resulting in data errors.
Thus, a method and system for reconstructing a RAID system is desirable.